Heating system

ABSTRACT

An industrial heating system, in particular a method and apparatus for intentionally or automatically shutting down a high temperature, high pressure fluid system for a user, such as a platen press, kettles, rolls, etc. where the user has a higher hydrostatic head than the fluid supply tank under non-operating conditions.

United States Patent Teller Oct. 31, 1972 [s41 HEATING SYSTEM 2,262,194 11/1941 News" ..237/s 2,345,277 3/1944 McGrath.... ..237/8 C UX [72] Invent 3'1" 1 Tell", scarmmugh 3,236,292 2/1966 Smith ..165/11 [73] Assignee: Amerioan Hydrotherm Corporation Primary Exami'wr--Edwal'd Mihael Att0rney-Marn & Jangarathis [22] Filed: Aug. 19, 1970 v [21] Appl. No.: 65,023 ABSTRACT v 4 An industrial heating system, in particular a method and apparatus for intentionally or automatically [52] US. Cl. ..237/8 R shutting down a high temperature high pressure fluid [5 ..F24d y t mfor a user such as a platen pl'eSS, kettles, I'Qus,

0t SCQI'CI'I R etc where the user has alligher hydrostatic head v the fluid supply tank under non-operating conditions.

R f Cited 1 [56] e erences 10 C F g UNITED STATES PATENTS 2,211,573 8/1940 McGrath "237/8 PATENTEDnm a 1 m2 sum 1 or 2 Fig.

INVENTOR.

William M. Teller ATTORNEYS user, for instance a platen HEATING SYSTEM This invention relates to a method and apparatus for intentionally or automatically shutting down a system for providing high temperature, high pressure fluid to a press, such as for forming laminates.

In many industrial processes, a closed heating system is an important aspect of the overall process. Thus, for example, in the production of laminates in a platen press, a steam generation system provides stem to .heat water under pressure which is passed through heat exchange cavities located within equipment to be heated. The hot water generator-expansion tank for such a system is" located above the highest point of the user to insure that fluid is in the lines at all times. Such elevated positioning of the tank, in most instances, requires elaborate foundation and supporting structures with a concomitant increase in the cost of such installation.

Accordingly, an object of this invention is to provide a system for providing a high temperature, pressurized fluid for a user. A further object of this invention is to provide a high temperature high pressure fluid system wherein the hot fluid generator tank has a lower hydrostatic head, at rest, than the user.

Yet another object of this invention is to provide for i a high temperature fluid system which eliminates the need for pressurizing means for introducing air or other inert gases into the system.

Still another object of the invention is to provide a method and apparatus for automatically shutting-down such a fluid system in the event of an upset thereto, such as tube failure in the heating system.

These and other objects of the invention should be readily apparent from the following detailed description of the invention when read with reference to the accompanying drawings wherein:

FIG. 1 is a schematic drawing of an embodiment ofa heating system of the invention for a platen press; and

FIG. 2 is. a schematic drawing of another embodiment of a heating system of the invention wherein two users are provided in parallel, as for instance rolls.

The objects of this invention are broadly accomplished in one aspect, by providing a three-way valve interconnecting the hot fluid pump discharge conduit, the user discharge conduit and the return conduit to the hot fluid generator-expansion tank together with a check valve disposed in the pump discharge conduit downstream of the branch to the three-way valve. In another aspect, the three-way valve is disposed on the suction side of the pump as more fully hereinafter described. 1

The invention will be further described with respect to embodiments thereof illustrated in the accompany.- ing drawings. It is to be understood, however, that such embodiments are only illustrative of the invention and therefore the scope of the invention is not to be limited thereby.

Referring now to FIG. 1, the system for providing a high temperature liquid includes a vessel for storing and heating the liquid, apump 11, user equipment, generally indicated as 12, such as a platen press, and a three-way valve, generally indicated as 13. The lower portion of vessel 10 is connected to pump 11 by conduits 13 and 15 under the control of valve 14. The

discharge end of the pump 11 is connected to the inlet of the user equipment 12 through conduit 16, valve 17,

conduit 18, check valve 19 and conduit 20. The outlet of the user 12 is connected to one port 13b ofthreeway valve 13 by conduit 21. The conduit 18 is connected via line 22 to a port 13a of the valve 13, whereas the commonport 13c of. thevalve 13 is connected by a conduit 23 to the vessel 10. A pressure switch 25 is mounted andconnected to the vessel 10 for det ermin ing the pressure in the vessel 10, and which switch 25 is operatively connected by line 28 to a solenoid valve 26..

A temperature control 27 is also provided to monitor the pressure on control. air passed to and-through the solenoid valve to the diaphragm of the three-way valve 13 via line 29 in response to the temperature of the fluid in vessel 10. i 5

In normal use, i.e. the pump 11 operating, the vessel 10, (such as a hot water generator with a steam cushion of the direct or indirect type commonly used in the art) is under a given pressure with ports 13b and 13c of the valve 13 being in fluid communication. Supply air is passed through temperature control 27 to the threeway solenoid valve 26 and thence to the diaphragm of the valve 13 via line 29. The solenoid valve 26 is maintained in an energized state by pressure switch 25 which senses the pressure in the vessel 10.

To intentionally shutdown the heating system, a pump stop button (not shown) is depressed which deenergizes the solenoid valve 26 thereby alters its port positioning to vent air to the atmosphere by line 30 from the diaphragm of the valve 13 via line 29. Reduction'of air pressure on the diaphragm of the three-way valve 13 causes port 13b to close thereby opening port 1381 to common port 13c. A time delay relay (not shown) keeps the pump running until completion of such port change. With port 13b closed, fluid from the discharge end of user 12 is prevented from flowing through conduit 21 while the check valve 19 prevents fluidlfrom flowing back through line 20 from the inlet end of user 12. At this point, the steam supply through line 31 to the vessel 10 may be shut off, or the firing of the vessel 10 may bediscontinued, depending on the type of hot fluid generator or heater used for the instal: lation. It will be readily apparent that a disruption in service which would result in a pressure reduction vessel 10 would also effect a shut down of the system.

For re-starting the system, the pump start button (not shown) is depressed energizing the pump motor of the pump 11 which results in a flow of fluid from the pump to the vessel 10 through three-way valve 13 (port 13a-'-port via conduit 16, valve 17, conduit 18 and conduit 22, and thence from the vessel 10 to the suction side of pump 11 via conduits 13 and 15 under the.

Referring now to FIG. 2 which illustrates another embodiment of the invention wherein two user equipments 112a and l12b are operated independently of each other, there is provided a vessel 110 for storing and heating the fluid, pumps 113 and 114, and threeway valves 115 and 116. A discharge conduit 118 from vessel 110 is split into conduits 1 19 and 120 which are connected to the suction side of pumps 1 13 and 1 14 via check valves 121 and 122, respectively. The discharge ends of pumps 113 and 114 are connected to the inlet side of users 112a and 112b by conduits 123 and 124, respectively. The outlet end of users 112a and 1 12b are connected to inlet ports 115a and 116a of three-way valves 115 and 116 by conduits 125 and 126, respectively. Ports 1150 and 1160 of the three-way valves 115 and 116 are connected by conduits 127 and 128, respectively, which join to form conduit 129 connected to the inlet of vessel 110. Ports llb and 116b of the valves are in fluid communication via conduits 131 and 132 with conduit 119 and 120 on the suction side of pumps 113 and 114, respectively. A heating medium, such as steam is supplied to vessel 110 through line 139.

A pressure switch 140 provided on the vessel 110 energizes solenoid valves 133 and 134, which control the flow of supply air admitted to the diaphragm of three-way valves 115 and 116, respectively, through temperature controllers 135 and 136. The temperature controllers 135 and 136 measure the temperature on the discharge side of pumps 113 and 114 and control the temperature of the fluid passed through users 112a and 112b, respectively.

Operation of the multiple user system illustrated in FIG. 2 is similar to that of FIG. 1, with ports 115a and 115C, and 116a and 116c of the valves 115 and 116, respectively, being in fluid communication therebetween. Should it be desirable to shut-down the system, a switch (not shown) is activated to stop the pumps 113 and 114, with pressure switch 140 de-energizing solenoid valves 133 and 134 which causes a portal change thereof permitting air on the diaphragms of the three-way valves 115 and 116 to vent through the solenoid valves 133 and 134 to the atmosphere. This results in a change in the portal relationship of valves I and 116 from a 115a to 115C and 116a to 1166 portal relationship to a 115a to 115b and 116a to 116b, respectively. Since the flow of fluid back through line 119 and 120 is prevented by check valves 121 and 122, and since the discharge side of users 112a and 112b are connected to the now closed ports 115C and 116:: ofthe valves 115 and 116, respectively, no fluid may be passed to the vessel 110.

To start-up the system of FIG. 2 a pump start button (not shown) is depressed energizing the pump motors of pumps 113 and 114 resulting in a flow of fluid through users 112a and 112b via conduits 123 and 124, conduits 125 and 126, valves 115 and 116 (a to b) portal relatiohship, conduits 131 and 132, and conduits 119 and 120. The fluid in vessel 110 is heated by an intermediate heat transfer fluid, such as steam, in line .139 thereby gradually raising the pressure of the fluid therein. Reaching operating pressure energizes pres- 6 sure switch 140 which in turn energizes solenoid valves 133 and 134 thereby altering the portal relationship thereof to permit supply air to pass to the diaphragms of the valves and 1 16, respectively. The valves 115 and 1 16 are changed from relationship of a to b position to an a to 0 position allowing heated fluid to pass to the vessel 1 I 0 via lines 127 and 128 thereby permit the fluid of heated fluid from the vessel 1 10 through lines I 19 and to users 1 12a and 112b under the control of check valves 121 and 122, respectively.

The description herein is directed to a user of high pressure, high temperature fluid, such as a platen press for laminates and the like, however, it will be readily appreciated that the system is applicable to the use of heat transfer fluids, such as Dow Therm, which form vapors in the heat generating tank. The system as shown in FIG. 2 may also be used for thermal fluid systems operating under atmospheric pressure in which case, the pressure switch is omitted with solenoid valves 133 and the pump starters.

The system of either FIG. 1 or 2 may automatically shut-down in response to an upset in the system. Such an upset would normally be detected by the pressure switch associated with the storage vessel in which event the solenoid valve or valves controlled by the pressure switch would be de-energized as well as the pump motors through a time delay relay as hereinabove described. The shut down sequence of either system would thereafter follow the sequence when intentionally shutting down such system.

Numerous other modifications and variations of the present invention are possible in light of the above teachings and therefore the invention may be practiced other than as particularly described.

What is claimed is:

1. Apparatus for supplying user equipment with high temperature, high pressure fluid comprising:

a. a storage vessel for storing fluid having a lower hydrostatic pressure than said equipment;

b. means for heating the fluid in said vessel therein;

c. first conduit means for passing fluid to said user from said vessel; second conduit means for withdrawing fluid from said user equipment; unidirectional flow control means in said first conduit means;

f. pump means for pressurizing said fluid;

g. third conduit means for introducing fluid into said vessel;

valve means having three ports, one port connected to said first conduit means, one port connected to said second conduit means, and one port connected to said third conduit means;

i. control means for maintaining said valve means in a condition whereby said second and third conduit means are in fluid communication therethrough during operation of said user equipment and to change said valve means during non-use to a condition whereby said first and third conduit means are in fluid communication therethrough thereby to prevent flow of fluid from said user to said vessel.

2. The apparatus as defined in claim 1 wherein said pump means is provided in said first conduit means.

3. The apparatus as defined in claim 2 wherein the unidirectional flow control means is positioned in said first conduit means on the discharge side of said pump means.

134 being simultaneously activated by 4. The apparatus as defined in claim 2 wherein a plurality of user equipment is provided with the unidirectional flow control means positioned on the suction side of said pipe means and with the valve means being positioned between said unidirectional flow control means and said pump means.

5. The apparatus as defined in claim 4 wherein the valve means for each user equipment is responsive to the temperature of the fluid issuing from said pump means. 7

6. The apparatus as defined in claim 1 wherein said valve means has a diaphragm which is provided with supply air from a'solenoid valve.

7. The apparatus as defined in claim 6 wherein the flow of supply air through the solenoid valve is modulated in response to the temperature of fluid in said first conduit means.

8. A method for shutting down a system wherein a hot heat transfer fluid is passed from an accumulation through-a second conduit, the improvement comprising:

sensing an upset condition by a pressure change in said accumulation zone; altering the flow of fluid through said conduits whereby fluid is prevented from passing to the user equipment from the accumulation zone in response to said sensed upset condition; discontinuing the flow of fluid through said conduits;

and automatically discontinuing the heating of said heat transfer fluid in said accumulation zone. 9. The improved method of claim 8 wherein fluid is circulated through said user equipment after said sensed upset condition until fluid flow is fully discontinued.

- 10. The improved method of claim 8 wherein fluid is circulated through said accumulation zone after said Zone through a first conduit to a user equipment having sensed upset condition until flllldflOW is fully discona higher hydrostatic head thereof and wherein the fluid is returned from said user equipment to said zone tinued. 

1. Apparatus for supplying user equipment with high temperature, high pressure fluid comprising: a. a storage vessel for storing fluid having a lower hydrostatic pressure than said equipment; b. means for heating the fluid in said vessel therein; c. first conduit means for passing fluid to said user from said vessel; d. second conduit means for withdrawing fluid from said user equipment; e. unidirectional flow control means in said first conduit means; f. pump means for pressurizing said fluid; g. third conduit means for introducing fluid into said vessel; h. valve means having three ports, one port connected to said first conduit means, one port connected to said second conduit means, and one port connected to said third conduit means; i. control means for maintaining said valve means in a condition whereby said second and third conduit means are in fluid communication therethrough during operation of said user equipment and to change said valve means during non-use to a condition whereby said first and third conduit means are in fluid communication therethrough thereby to prevent flow of fluid from said user to said vessel.
 2. The apparatus as defined in claim 1 wherein said pump means is provided in said first conduit means.
 3. The apparatus as defined in claim 2 wherein the unidirectional flow control means is positioned in said first conduit means on the discharge side of said pump means.
 4. The apparatus as defined in claim 2 wherein a plurality of user equipment is provided with the unidirectional flow control means positioned on the suction side of said pipe means and with the valve means being positioned between said unidirectional flow control means and said pump means.
 5. The apparatus as defined in claim 4 wherein the valve means for each user equipment is responsive to the temperature of the fluid issuing from said pump means.
 6. The apparatus as defined in claim 1 wherein said valve means has a diaphragm which is provided with supply air from a solenoid valve.
 7. The apparatus as defined in claim 6 wherein the flow of supply air through the solenoid valve is modulated in response to the temperature of fluid in said first conduit means.
 8. A method for shutting down a system wherein a hot heat transfer fluid is passed from an accumulation zone through a first conduit to a user equipment having a higher hydrostatic head thereof and wherein the fluid is returned from said user equipment to said zone through a second conduit, the improvement comprising: sensing an upset condition by a pressure change in said accumulation zone; altering the flow of fluid through said conduits whereby fluid is prevented from passing to the user equipment from the accumulation zone in response to said sensed upset condition; discontinuing the flow of fluid through said conduits; and automatically discontinuing the heating of said heat transfer fluid in said accumulation zone.
 9. The improved method of claim 8 wherein fluid is circulated through said user equipment after said sensed upset condition until fluid flow is fully discontinued.
 10. The improved method of claim 8 wherein fluid is circulated through said accumulation zone after said sensed upset condition until fluid flow is fully discontinued. 